Objective: To optimize matrix formulation of Zhitong gel ointments and investigate its in vitro release properties. Method: With initial bonding strength

endurance bonding strength and film residual as indexes

optimal proportion of matrix formulation(NP-700

aluminum compounds

glycerin and tartaric acid) was selected by central composite design-response surface methodology.Modified Franz diffusion cell and millipore membrane were used to investigate in vitro release properties of ferulic acid in Zhitong gel ointments. Result: Optimum matrix formulation was NP-700-aluminum compounds-glycerin-tartaric acid (1.5:0.16:8.8:0.12).Cumulative release rate of ferulic acid in Zhitong gel ointments was (86.31±6.73)% in 12 h. Conclusion: This optimized matrix formulation had high drug loading and good spreadability

moisture resistance and adhesion.In vitro release behavior of ferulic acid in Zhitong gel ointments was close to the zero-order equation with a dual mechanism of diffusion and dissolution

but mainly by diffusion.